Shrub encroachment in arid and semiarid rangelands, a worldwide phenomenon, results in a heterogeneous landscape characterized by a mosaic of nutrient-depleted barren soil bordered by nutrient-enriched shrubby areas known as ‘‘fertile islands.’’ Even though shrub encroachment is considered as a major contributor to rangeland degradation, little is known about mechanisms favoring the reversibili...

This study measured runoff and sediment concentration from the tire track and from the non-tire track to determine infiltration, interrill erodibility, and vegetative cover impacts of reopening an abandoned forest road. Runoff was lowest on the non-track portion of the abandoned road and highest on the reopened road. Sediment concentrations were significantly higher on the reopened road. Increa...

This research work exposes the results of our study about cartographic and qualitative estimation hydric erosion watershed talangaï (Brazzaville) following PAP/RAC approach, tele detection’s data geographical information system in order to elaborate thematic cards by enlightening phenomenon. In this talangaï, phenomenon became recurrent causes more spectacular worrings. As a matter fact, except...

The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrela...

Improved computer models of erosion have been developed, considering soil hydraulic conductivity. The models deal with erosion of levees, dams and embankments due to overtopping. The simulations trace the formation of rills and gullies, beginning with initial overtopping and continuing to final breaching. Physical models performed at 1-g and high g using a geotechnical centrifuge have been used...

Soil erosion risk assessment at the watershed of Alqueva is urgently needed to conserve water resources and prevent the accelerated dam siltation. The variation of soil properties is one of the most important reasons for the spatial variability of vegetation cover and erosion. In order to achieve more and better management of rangelands around the largest reservoir of Europe, it is essential to...